Interesting point. I feel that dismissing the whole thing as a "lack of transparency" issue is a bit too simple though.

It might not be "illegal" but it is not farfetched that they are abusing they power position. Sure is their platform but we sometimes forget that it represents some 1.5B devices. As also other cases point out the 30% tax, which for a small firm is money, is not the only unfair practice. Different set of APIs for their apps and everyone else's is another important thing.